Skip to content

L
linux
Switch branch/tag
  1. 25 Mar, 2021 2 commits
    • Vladimir Murzin's avatar
      ARM: 9069/1: NOMMU: Fix conversion for_each_membock() to for_each_mem_range() · 45c2f70c
      Vladimir Murzin authored 
      for_each_mem_range() uses a loop variable, yet looking into code it is
not just iteration counter but more complex entity which encodes
information about memblock. Thus condition i == 0 looks fragile.
Indeed, it broke boot of R-class platforms since it never took i == 0
path (due to i was set to 1). Fix that with restoring original flag
check.

Fixes: b10d6bca ("arch, drivers: replace for_each_membock() with for_each_mem_range()")
Signed-off-by: default avatarVladimir Murzin <vladimir.murzin@arm.com>
Acked-by: default avatarMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
      45c2f70c
    • Ard Biesheuvel's avatar
      ARM: 9063/1: mm: reduce maximum number of CPUs if DEBUG_KMAP_LOCAL is enabled · d624833f
      Ard Biesheuvel authored 
      The debugging code for kmap_local() doubles the number of per-CPU fixmap
slots allocated for kmap_local(), in order to use half of them as guard
regions. This causes the fixmap region to grow downwards beyond the start
of its reserved window if the supported number of CPUs is large, and collide
with the newly added virtual DT mapping right below it, which is obviously
not good.

One manifestation of this is EFI boot on a kernel built with NR_CPUS=32
and CONFIG_DEBUG_KMAP_LOCAL=y, which may pass the FDT in highmem, resulting
in block entries below the fixmap region that the fixmap code misidentifies
as fixmap table entries, and subsequently tries to dereference using a
phys-to-virt translation that is only valid for lowmem. This results in a
cryptic splat such as the one below.

  ftrace: allocating 45548 entries in 89 pages
  8<--- cut here ---
  Unable to handle kernel paging request at virtual address fc6006f0
  pgd = (ptrval)
  [fc6006f0] *pgd=80000040207003, *pmd=00000000
  Internal error: Oops: a06 [#1] SMP ARM
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper Not tainted 5.11.0+ #382
  Hardware name: Generic DT based system
  PC is at cpu_ca15_set_pte_ext+0x24/0x30
  LR is at __set_fixmap+0xe4/0x118
  pc : [<c041ac9c>]    lr : [<c04189d8>]    psr: 400000d3
  sp : c1601ed8  ip : 00400000  fp : 00800000
  r10: 0000071f  r9 : 00421000  r8 : 00c00000
  r7 : 00c00000  r6 : 0000071f  r5 : ffade000  r4 : 4040171f
  r3 : 00c00000  r2 : 4040171f  r1 : c041ac78  r0 : fc6006f0
  Flags: nZcv  IRQs off  FIQs off  Mode SVC_32  ISA ARM  Segment none
  Control: 30c5387d  Table: 40203000  DAC: 00000001
  Process swapper (pid: 0, stack limit = 0x(ptrval))

So let's limit CONFIG_NR_CPUS to 16 when CONFIG_DEBUG_KMAP_LOCAL=y. Also,
fix the BUILD_BUG_ON() check that was supposed to catch this, by checking
whether the region grows below the start address rather than above the end
address.

Fixes: 2a15ba82 ("ARM: highmem: Switch to generic kmap atomic")
Reported-by: default avatarPeter Robinson <pbrobinson@gmail.com>
Tested-by: default avatarPeter Robinson <pbrobinson@gmail.com>
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
      d624833f
  3. 06 Mar, 2021 4 commits
  5. 05 Mar, 2021 33 commits
  7. 04 Mar, 2021 1 commit
    • Jens Axboe's avatar
      kernel: provide create_io_thread() helper · cc440e87
      Jens Axboe authored 
      Provide a generic helper for setting up an io_uring worker. Returns a
task_struct so that the caller can do whatever setup is needed, then call
wake_up_new_task() to kick it into gear.

Add a kernel_clone_args member, io_thread, which tells copy_process() to
mark the task with PF_IO_WORKER.
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      cc440e87
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7